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Submission #673848

# Submission time Handle Problem Language Result Execution time Memory
673848 2022-12-22T09:23:22 Z benjaminkleyn Pipes (CEOI15_pipes) C++17
100 / 100
 1061 ms 14208 KB 
#pragma GCC optimize("O3,unroll-loops")
#pragma GCC target("avx2,bmi,bmi2")
#include <bits/stdc++.h>
using namespace std;
typedef long long ll;

const int max_n = 100000;

int mem[2 * max_n];
int *par[2];

int find(const int &u, const int &dsu)
{
    return (par[dsu][u] == u ? u : par[dsu][u] = find(par[dsu][u], dsu));
}

bool same_set(const int &u, const int &v, const int &dsu)
{
    return find(u, dsu) == find(v, dsu);
}

void unite(const int &u, const int &v, const int &dsu)
{
    par[dsu][find(v, dsu)] = find(u, dsu);
}


int n, m, timer = 0;
vector<int> g[max_n];
int edge_xor[2 * max_n], edge_cnt = 0;
int *ti, *lo;

void dfs(const int &u, const int &p)
{
    ti[u] = lo[u] = ++timer;
    for (const int &e : g[u])
        if (e != p)
        {
            int v = edge_xor[e] ^ u;
            if (ti[v])
                lo[u] = min(lo[u], ti[v]);
            else
            {
                dfs(v, e);
                lo[u] = min(lo[u], lo[v]);

                if (lo[v] > ti[u])
                    cout << u + 1 << ' ' << v + 1 << '\n';
            }
        }
}


int main()
{
    cin.tie(0)->sync_with_stdio(0);

    cin >> n >> m;

    par[0] = &mem[0];
    par[1] = &mem[max_n];
    for (int i = 0; i < n; i++)
        par[0][i] = par[1][i] = i;
    
    for (int i = 0, a ,b; i < m; i++)
    {
        cin >> a >> b;
        a--, b--;

        if (!same_set(a, b, 0))
            unite(a, b, 0);
        else if (!same_set(a, b, 1))
            unite(a, b, 1);
        else continue;

        g[a].push_back(edge_cnt);
        g[b].push_back(edge_cnt);
        edge_xor[edge_cnt] = a ^ b;
        edge_cnt++;
    }

    ti = &mem[0];
    lo = &mem[max_n];

    for (int i = 0; i < n; i++)
        ti[i] = lo[i] = 0;

    for (int i = 0; i < n; i++)
        if (!ti[i])
            dfs(i, -1);

    return 0;
}

Subtask #1
10.0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 2 ms 2644 KB Output is correct
2 Correct 2 ms 2644 KB Output is correct

Subtask #2
10.0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 5 ms 3212 KB Output is correct
2 Correct 6 ms 3028 KB Output is correct

Subtask #3
10.0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 85 ms 3380 KB Output is correct
2 Correct 81 ms 3236 KB Output is correct

Subtask #4
10.0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 153 ms 4096 KB Output is correct
2 Correct 162 ms 3652 KB Output is correct

Subtask #5
10.0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 239 ms 5664 KB Output is correct
2 Correct 234 ms 5120 KB Output is correct

Subtask #6
10.0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 336 ms 10640 KB Output is correct
2 Correct 318 ms 7116 KB Output is correct

Subtask #7
10.0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 510 ms 11916 KB Output is correct
2 Correct 547 ms 9164 KB Output is correct

Subtask #8
10.0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 717 ms 14208 KB Output is correct
2 Correct 648 ms 9388 KB Output is correct

Subtask #9
10.0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 865 ms 14156 KB Output is correct
2 Correct 803 ms 9032 KB Output is correct

Subtask #10
10.0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 1008 ms 13516 KB Output is correct
2 Correct 1061 ms 10384 KB Output is correct